Condenser



Aug. 15, 1933. R. N. EHRHART CONDENSER Filed Oct. 2, 1930 fbg INVENTOR Patented Aug. 15, 1933 UNITE@ STATES FATENT-OFFICE CNDENSER Raymond N. Ehrhart, Pittsburgh, Pa. Application October 2, 1930; Serial No.. 485,846

7 Claims. (C1. 25T-m43) This invention relates to heat exchangers and more particularly relates to surface condensers of the type generally known as single-pass condensers or other such condensers having a plurality of compartments of unequal heat absorbing capacities.

In surface condensers, particularly those of relatively large cooling surface area, the tubes which conduct the cooling fluid through the condenser are generally supported at one or more points intermediate their ends by means oi perforated plates disposed transversely of the condenser shell and through which the tubes extend. Ihese tube supporting plates divide the condenser into a plurality of condensing compartments. Since the cooling fluid passes in series through each of the compartments, and is progressively heated in its passage through the condenser, it is obvious that each of the compartments will have different condensing capacities. The compartment rst to receive cooling huid will have the greatest heat absorbing capacity, the compartment last to receive cooling fluid, that is, after it has passed through all the other condensing compartments, will have the least heat absorbing capacity and the compartments located intermediate the end compartments will have intermediate heat absorbing capacities. I

In condensers of this type, since the vapor inlets of all the compartments are usually in open communication, thus establishing the same pressure at the inlets of all the compartments, it is apparent that if all the compartments were supplied with vapors in proportion to their heat absorbing capacities, the pressures at the outlets of the compartments must dii'er. If the gas outlets of all the compartments are connected in an unobstructed manner with a gas exhausting means and tl e terminal pressure of the cold compartment for example, were such that the volume of vapor supplied thereto were proportional to its condensing capacity, since the same terminal pressure exists in the hot compartment, an excessive quantity of vapor will flow into and through. the hot compartment to the gas exhausting means. This will interfere with the gas removal from the cold compartment and will prevent the penetration of vapors to the terminus of the colder compartments and inefcient operation will result.

In order to overcome these disadvantages and to secure eicient condenser operation, various means have heretofore been utilized to secure equal vapor penetration in each of the compartments of a multi-compartment surface condenser.

Such means have included separate gas exhaustmeans for each compartment, adjustable valves between each compartment and the gas exhausting means, different sized orices in the conduits between the compartments and the gas exhausting means and many other means. All such devices, however, have served to more or less complicate the condenser structure.

.'Esy means of my invention I am enabled to obtain efficient operation in multi-compartment surface condensers without utilizing devices which complicate the condenser structure.

l To accomplish this, instead of attempting to regulate the vapor flow in each of the compartmentsso as to obtain equal vapor penetration, I cause a iiow of vapor into the compartments in excess of their heat absorbing capacities and provide or penetration in the compartments with suicient penetration in the coldest compartment and greater penetration in the hottest compartment. I provide for a small vapor iiow from the coldest compartment, agreater flow from the hottest compartment and a vapor iiow of intermediate values from the intermediate compartments. I condense the vapors flowing from the compartments in a residual condenser and pass the vapors thereto through conduits or openings so proportioned that ,with compartments having equal condensing surfaces, the conduits will impose substantially equal pressure drops for substantially the same ilows therethrough and with compartments having unequal condensing surfaces, the conduits will -cause substantially equal pressure drops for flows therethrough which are proportional to the condensing surfaces oi? the compartments. I use no structure complicating devices, such as valves, orices, or other means with these conduits.

The nature or my invention will become apparent from the following description taken in connection with the accompanying drawing forming a part thereorn which illustrates a preferred form of apparatus for carrying out my invention, it being understood, however, that the invention may be embodied in different kinds of structures.

In the drawing:

l is a more or less diagrammatic view, in longitudinal. section, of a single-pass compartment type surface condenser embodying the present invention, the section being taken substantially on line ll of Fig. 2,

Fig. 2 is a sectional view` of the condenser taken on line 2--2 of Fig. l, and

Fig. 3 is a View similar to Fig. 1 showing a modied form of the invention.

Like characters of reference refer to like parts throughout the several views.

Referring to Figs. 1 and 2 of the drawing, reference character 10 denotes the shell oi a three compartment, single-pass surface condenser constructed in accordance with the present invention. The shell has tube sheets 11 and 12 sW .l ably secured to its ends. Tubes 13 are secured at their ends to the tube sheets 11 and 12 and are supported intermediate their ends by tube supporting plates 14 and l5 which divide the condenser shell into condensing compartments 16, 17 and 18. Water or other cooling iuid enters the condenser through inlet water box 19 and after flowing through the tubes 13 leaves the condenser through outlet water box '26. Since the cooling fluid in flowing through the condenser through tubes 13 becomes progressively hotter, is apparent that compartment 15, thecompartmentV rst to receive cooling iiuid, will be the coldest compartment and have the greatest heat absorbing capacity, compartment 18, the last to receive cooling uid, will be the hottest and have the smallest heat absorbing capacity and intermediate compartment 17 will have a heat absorbing capacity intermediate that of compartments 16 and 18. Y

Vapors enter the condenser through vapor inlet 21 and ovv into each of the compartments '16, 17 and 18 Where some of the vapors will condensed by the cooling tubes 13 and the condensate will collect in the bottoms of the comcapacities of the compartments, there will be unequal pressure drops through the compartments.

The greatest pressure drop will occur in compartment 16 and the lowest in compartment 18. Compartment 18 will therefore have the highest terminal pressure, compartment 17 a lower terminal pressure and compartment 16 the lowest terminal pressure. rThe condensate in compartment 18 will thus flow through loop seal 22 into the bottom of compartment 17, the condensate in compartment 17 will flow through loop seal 23 into compartment 16 and the condensate in the latter compartment will be withdrawn through outlet 24 by a suitable tail pump, not shown.

The uncondensed vapors in compartments 16, 17 and 18 will flow through conduits 25,7 26 and 27 respectively into cooler 28 and will there be condensed. Cooler 28 comprises a shell 29, tube sheets 30 and 31, tubes 82 extending between the tube sheets and inlet and outlet water boxes 33 and 34 respectively. Cooling fluid is supplied to the tubes 32 through a conduit 35 from inlet Water box 19 vand after passing through tubes 32, the cooling fluid is conducted to outlet water box 20 through a conduit 36. Condensate is withdrawn from the cooler through outlet 37 and conduit .38 connects the cooler to a gas exhausting means. A cap 39 is placed over the inlet ends of each of the conduits 25, 26 and 27 to prevent condensate which drips from the tubes 12 from entering the conduits, and a similar cap 40 is placed over the inlet end of outlet 38 in cooler 28. I prefer that conduits 25, 26 and 27 which connect the termini of the compartments 16, 17 and 18 with the cooler 28 be of substantially the same internal diameter throughout their lengths and devoid of any means for impeding or changing the direction or velocity of iiovv therethrough. I prefer lthese conduits to have cross-sectional areas which are in proportion to the condensing surface of the compartments they serve. In the form of my invention illustrated in Figs. 1 and 2, the partitions 14 and l5 are so located that the compartments have equal condensing surfaces, consequently the cross-sectional areas of the conduits 2 26 and 27 will be the same.

Due to inf'itration and leakage in the condenser, the prime mover it serves and the connecting piping, a certain amount of air will ind its way into the condenser and will have to be removed by the gas exhausting means. n a three compartment condenser as shown, approximately onethird oi the total amount of air leaking into the condenser will be removed through each oi-` the conduits 25, 26 and 27. I prefer to proportion conduit 25, the conduit connected with the terminus of comparY -ent 16, the cold compartment, so that with a conduit iength not greater than a few `imes its diameter, its cross-sectional area will be such that the pressure drop therethrough, with a flow of approximately ten pounds oi steam per n md of air, will be approximately 1/100 inches of mercury. it is understood, however, that I do not Wish to be limited to these precise values. Since, in the condenser` shown in Figs. 1 and 2, the condensing surface of each compartment is the same, the cross-sectional areas of the conduits 25, 25 and 27 will. in accordance with my invention, be the same, or, will be so proportioned that the conduits will cause substantially equal pressure drops for substantially the same ows therethrough.

Due to the unequal heat absorbing capacities of the several. compartments, the pressure drops through the compartments will be diierent and the terminal pressures in the compartments will be diierent, there being a higher lerminal pressure in compartment 17 than in compartment 16 and a still higher terminal pressure in compartment 18. Because the outlet ends of conduits 25, 26 and 27 are in open communication and the same pressure exists at the outlet ends of each of the conduits there will be a greater pressure drop through conduit 26 than through conduit 25 and a greater pressure drop through conduit 27 than through conduit 26. Thus, the vapor now through conduit 26 will be greater than the vapor flow through conduit 25 and the vapor flow through conduit 27 wil be greater than through conduit 26. I thus keep the mixture to be cooled and condensed, steam rich rather than air rich clear to the terminus or" each compartment and maintain the condensing eiiiciency oi each compartment a high point.

i noportioned so that its condensing 'ace is sncient to condense substantially all the vapors flowing thereto from all Jfhe compartments of the condenser. v

With this arrangement I obtain unequal vapor penetration in the compartments with a greater vapor penetration in the hcttest compar ent in the coldest compartment and vapor peneons in intermediate compartments ol inodiate values. provide for a suicient varesidual condenser to maintain the mixtureto cooled steam rich throughout the compartment s terminus, greater vapor new rrom the ttest compartment and vapor flows of intero iate values from the intermediate compart- I thus obtain eiiicient condenser operaiou't use of means which complicat. the con-denser structure.

as a variety of meanings have here- 'toore been given the expression vapor peneflow from thev coldest compartment to the "1 lll) tration in the art to which this invention relates, I deem it expedient to denne what I mean by this expression. Due to infiltration and leakage, a certain amount of air is Withdrawn from the terminus of each compartment of a compartment type condenser and in practically every case, some vapor also reaches the compartment terminus, although in many Ainstances the amou t of this vapor is very small. But where there is a substantial :dow orl penetration of vapor throughoutl a compartment clear up to its terminus, there will generally be a substantial amount of vapor as compared with the-amount oi air iiowing from the terminus of the compartment and the `ratio of vapor to air or non-condensibles at tie compartment terminus is a measure oi' the vapor penetration of the compartment. the expression vapor penetration as used herein, I mean the ratio of the weight of steam to the Weight of air flowing from the terminus oi a compartment.

In the modified form of my invention shown in Fig. the condenser shell is divided by means oi partition 5l into two condensing compartments 52 and 53 of unequal condensing surfaces. As shown in this ligure, compartment 52, the cooler compartment, has approximately half the cooling surface as compartment 53, the Warmer compartment. lI prefer to proportion Yconduit 5.4i, the conduit connecting the cooler compartment with the residual condenser 28 so that the pressure drop therethrough, with a iow of approximately ten pounds of steam per pound oi` air, will be approximately 1/190 inches of mercury, hut, as previously indicated, I do not Wish to be limited to these values. Conduit 55 will have, in accordance With my invention, a crosssectional area approximately twice as great as the cross-sectional area of conduit 54, or the conduits 54 and 55 will be so proportioned as to cause substantially equal pressure drops for flows therethrough Which are proportional 'to the condensing surfaces or the compartments. The condenser receives vapor from a turbine or other prime mover 5 In. this form of my invention, as in the form i in Figs. l and 2, I obtain eiiicient condenser operation without the use of structure complicating devices by causing a flow of vapor into each compartment in excess of its heat abcapacity by causing unequal vapor enetration in the compartments with the greater penetration in the warmer compartment and a surlcient flow oi vapor from the terminus of the colder compartment to insure the mixture in that compartment being steam rich clear to the terminus of the compartment and a greater vapor flow from the Warmer compartment to the residual condenser.

In a three compartment single-pass surface condenser having a total condensing surface of approximately 56,343@ square feet, in which the condensing surface in each of the three compartments is approximately the same, each of conduits 25, 26 and 27 connecting the termini the compartments with the residual condenser 2S, would have a diameter of approximately 4 inches and the residual condenser would have a condensing surface of notless than 450 square feet.

While the invention has been described and illustrated as embodied in a condenser in which the residual vapors are condensed in a condenser located outside oi the shell of the main condenser, it will be apparent that the condensation of the residual vapors from each of the condensing compartments may be effected inside the main condenser shell, if desired, by a suitable arrangement of the condenser structure.

One of the important advantages oi my invention resides in the fact that the direction of flow of the cooling Water through the condenser may be reversed without in any Way affecting the efficiency of the condenser.

Although I have disclosed my invention as embodied inftwo and three compartment singlepass-surface condensers, it is apparent that the invention 4is equally Well applicable to condensers having a smaller or larger number of compartments as Well as to multi-flow condensers.

It is understood that lthe invention is limited only by the scope of the appended claims.

'What I claim is:

1V; A condenser comprising a shell, tube sheets, inlet and outlet Water boxes, tubes Within the shell extending between the tube sheets and connecting the Water boxes, partitioning means in the shell providing condensing compar of unequal condensing surfaces, a residual condenser and conduits connecting each compartment to the residual condenser, said conduits having their discharge ends in free communication With each other and being proportioned so as to cause substantially equal pressure drops for flows therethrough which are proportional to the condensing surfaces of the compartments.

2. A condenser comprising a shell, tube sheets, inlet and outlet Water boxes, tubes within the shell extending between the tube sheets and connecting the Water boxes, partitioning means in the shell providing condensing compartments of approximately equal condensing surface but of unequal heat absorbing capacity, a residual condenser and conduits connecting each compartment to the residual condenser, said conduits having their discharge ends in free communication With each other and being so proportioned as to cause substantially equal pressure drops for substantially the same ilows therethrough.

3. A surface condenser having a plurality of condensing compartments of unequal heat absorbing capacities and adapted to receive steam in such volume as to cause a flow of vapor into each compartment in excess of its heat absorbing capacity and having means comprising conduits connected to each compartment and in free communication with each other at 'their outlet ends, said conduits being so proportioned as to cause substantially equal pressure drops for substantially the same iiows therethrough.

4. AV surface condenser having a plurality of condensing compartments of unequal heat absorbing capacities and adapted to receive steam in such volume as to cause a iioW of vapor into each compartment in excess of its heat absorbing capacity and having means comprising conduits connected to each compartment and in free communication with each other at their outlet ends, the conduits being proportioned so as to cause substantially equal pressure drops for substantially the same flows therethrough, whereby a greater flow of vapors is obtained irom the compartment oi least heat absorbing capacity than from the compartment of greatest heat absorbing capacity and means for condensing the vapors iiowing from each compartment.

5. A surface condenser having a plurality of condensing compartments of unequal heat absorbing capacities and adapted to receive steam CIE in such volume as to cause a ow of vapor into each compartment in excess of its heat absorbing capacity and having a conduit connected to the terminus of eachY compartment and connected at its discharge end to a condensing zone, the discharge ends of all the conduits being in free communication with each other, .the conduits being so proportioned as to cause substantially equal pressure drops for substantially the same iiows therethrough, whereby unequal penetration is obtained in the compartments and a greater volume of vapor is caused to iiow from the compartment of least heat absorbing capacity than from the compartment of greatest heat absorbing capacity.

6. A condenser comprising a shell, tube sheets, inlet and outlet water boxes, tubes within the shell extending between the tube sheets and connecting the water boxes and adapted to have cooling water passed therethrough, partitioning means inthe shell providing condensing compartments of unequal heat absorbing capacities, a residual condenser and conduits connecting each compartment to the residual condenser, said conduits being proportioned so as to cause substantially equal pressure drops for substantially the same flows therethrough, thereby providing a condenser in which the direction of ilow of the cooling water through the condenser tubes may be reversed without substantially affecting the condensing eiiiciency thereof.

'7. A condenser comprising a shell, tube sheets, inlet and outlet water boxes, tubes within the shell extending between the tube sheets and connecting the water boxes and adapted to have cooling water passed therethrough, partitioning means in the shell providing condensing compartments of unequal condensing surfaces and unequal heat absorbing capacities, a residual condenser and conduits connecting each compartment to the residual condenser, said conduits being proportioned so as to cause substantially equal pressure drops for flows therethrough which are proportional to the condensing surfaces of the compartments, thereby providing a condenser in which the direction of flow of the cooling water through the condenser tubes may be reversed without substantially affecting the condensing eihciency thereof.

RAYMOND N. EHRHART. 

